The present invention relates to a method for the manufacturing of a reproduction of a three-dimensional physical object, in particular, a head of a foetus, where the method comprises the steps of obtaining at least one digital at least two-dimensional representation of the object, manipulation of said at least two-dimensional representation to input-data for a manufacturing machine and manufacturing of a reproduction of the head of a foetus based on said input-data.
In the recent years an increasing number of machines have become available in order to produce three-dimensional physical objects from digital representations.
Such digital representations could be obtained using various methods. Currently, the most common is to draw the object to be produced in a three-dimensional (3D) Computer Aided Design (CAD) program. Also, it is possible to have the object represented by two-dimensional (2D) construction drawings, on basis of which an execution program defining the machine coordinates is created that is specifically adapted for the machine on which the object should be manufactured. This implies that the object geometry is fully known and the geometry is sufficiently understandable for the operator to program the machine.
Along with the still increasing capabilities of the machines, the objects to be produced could have an increasing complex geometry. Therefore, an increasing number of machines are capable of directly converting the 3D CAD drawing to coordinates understandable by the manufacturing machine. Thereby, it is achieved that complex geometrical constructions could be produced although they are difficult to describe mathematically. An example of such methods for producing a geometrical construction from a three-dimensional CAD-drawing is rapid prototyping and/or rapid manufacturing.
Typically, the definition of a rapid prototyping process is, that it takes virtual designs from computer aided design or animation modelling software, transforming them into e.g. cross sections, still virtual, and then creates each cross section in physical space, one after the next until the model is finished. In the matter of rapid manufacturing the process is the same using a process material more resistible to more tear and wear.
Therefore, in the field of rapid prototyping and rapid manufacturing it is especially beneficial to be able to convert the digital representation of the desired object directly to understandable execution code for the manufacturing facility. Such manufacturing facilities could e.g. be Stereo Lithography (SLA), Selective Laser Sintering (SLS) or Selective Laser Melting (SLM).
In case the object to be produced is a reproduction of an existing physical object with an unknown geometry the digital representation is created on basis of measuring of the object. If the geometry of the object is complex, it may even be necessary to use a 3D-coordinate measuring machine. For obvious reasons are not all points on the object measured. Critical points are measured and curves are interpolated in order to achieve a full mathematical description of the geometry. However, the use of e.g. a 3D coordinate measuring machine or other forms of contact measuring instruments are not possible if the object in question is encapsulated and cannot be physically accessed.
Within the scope of the present invention an encapsulated head of a foetus is a head of a foetus which cannot be touched by the bare hand nor be seen by the naked eye. This means that the head of the foetus is surrounded on all sides.
This may be the case for objects that are encapsulated in a human body, such as organs, implants, a foetus or other physical objects in the human body. In order to perform physical measurements of the size, shape or physical structure of objects encapsulated in the human body, invasive procedures may be necessary. A number of different non-invasive and non-contact methods have been developed for obtaining a representation of a part of the human body or an object in the human body, such as X-ray, Magnetic Resonance Imaging (MRI) scans, Computed Tomography (CT) scans, Position Emission Tomography (PET) scans, Ultrasound and similar methods. The use of any of these non-contact methods, enable the viewing of or measurements of physical objects that are encapsulated in the human body.
Typically, the output of the above-mentioned non-invasive methods is in the form of a 2D representation of the 3D object, such as an X-ray radiograph, a CT or MRI slice or a ultrasound screenshot. As a simple 2D representation of a 3D object is not sufficient to describe the 3D object as a 3D CAD drawing, there is a need for a method for obtaining a digital representation of an encapsulated object and reproducing this object as a 3D physical model.
U.S. patent application Ser. No. 09/839,222 describes a method for obtaining a digital data representation of the auditory canal in order to be able to customize the shell of a hearing aid to a specific ear. The shape of an impression of an auditory canal is digitalized in order to produce a shell for a hearing aid that follows the contours of the auditory canal. This method only lists the steps to be followed if the impression is fully exposed, in order for the access of the measuring means to see it. Most of the non-contact methods for measuring the impression are considered directly harmful for human tissue or organs and therefore only used when necessary for treatment purposes.
U.S. Pat. No. 4,821,200 describes a method for reproducing the shape of a stump of a human extremity. The method and the apparatus is highly adapted to measure and reproduce said stump. The measuring is carried out using video cameras, which means that the method is not suited for measurement of encapsulated objects, such as object within the human body. The measurements of the external surface of a human extremity stump, an amputated leg or the like, are performed for the reproduction of the stump in order to facilitate the manufacturing of an improved prosthetic socket, because a moulding cast, which is normally used, would deform the soft biological tissue being moulded.